A new research program is proposed to study lipoprotein lipase in cultured cells derived from the stromal-vascular fraction of rat adipose tissue which have characteristics of preadipocytes. Upon exposure to heparin, these cultured adipose cells release lipoprotein lipase into the medium in a relatively pure form. The proposed research will include purification of the secreted lipoprotein lipase. The purified enzyme will be characterized with respect to monomer molecular weight, amino acid composition and carbohydrate content, heparin affinity and kinetics of triglyceride hydrolysis with synthetic emulsions and with intact lipoproteins (VLDL and chylomicrons). The cultured stromal-vascular cells will be subjected to subcellular fractionation techniques to determine the subcellular distribution of lipoprotein lipase. Similar fractionation studies will be performed on cultures treated with heparin, metabolic inhibitors or physiologic effectors such as hormones. Subcellular distributions of lipoprotein lipase in the presence of these compounds either singly or in various combinations will be compared. These data will be useful in attempting to establish the intracellular pathway by which a newly-synthesized lipoprotein lipase molecule is transported to the cell surface or degraded. Cells from adipose stromal-vascular fraction and also from the lipid-laden adipocyte fraction will be subjected to cloning procedures to establish lipoprotein lipase-producing cell lines.